/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the  "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id$
 */
package wx.xml.xalan.xpath.patterns;

import wx.xml.xalan.xml.dtm.DTM;
import wx.xml.xalan.xml.dtm.DTMIterator;
import wx.xml.xalan.xpath.Expression;
import wx.xml.xalan.xpath.ExpressionOwner;
import wx.xml.xalan.xpath.XPathContext;
import wx.xml.xalan.xpath.XPathVisitor;
import wx.xml.xalan.xpath.objects.XNumber;
import wx.xml.xalan.xpath.objects.XObject;

/**
 * Match pattern step that contains a function.
 *
 * @xsl.usage advanced
 */
public class FunctionPattern extends StepPattern {
    static final long serialVersionUID = -5426793413091209944L;
    /**
     * Should be a {@link wx.xml.xalan.xpath.functions.Function expression}.
     *
     * @serial
     */
    Expression m_functionExpr;

    /**
     * Construct a FunctionPattern from a
     * {@link wx.xml.xalan.xpath.functions.Function expression}.
     * <p>
     * NEEDSDOC @param expr
     */
    public FunctionPattern(Expression expr, int axis, int predaxis) {

        super(0, null, null, axis, predaxis);

        m_functionExpr = expr;
    }

    /**
     * Static calc of match score.
     */
    public final void calcScore() {

        m_score = SCORE_OTHER;

        if (null == m_targetString)
            calcTargetString();
    }

    /**
     * This function is used to fixup variables from QNames to stack frame
     * indexes at stylesheet build time.
     *
     * @param vars List of QNames that correspond to variables.  This list
     *             should be searched backwards for the first qualified name that
     *             corresponds to the variable reference qname.  The position of the
     *             QName in the vector from the start of the vector will be its position
     *             in the stack frame (but variables above the globalsTop value will need
     *             to be offset to the current stack frame).
     */
    public void fixupVariables(java.util.Vector vars, int globalsSize) {
        super.fixupVariables(vars, globalsSize);
        m_functionExpr.fixupVariables(vars, globalsSize);
    }


    /**
     * Test a node to see if it matches the given node test.
     *
     * @param xctxt XPath runtime context.
     * @return {@link wx.xml.xalan.xpath.patterns.NodeTest#SCORE_NODETEST},
     * {@link wx.xml.xalan.xpath.patterns.NodeTest#SCORE_NONE},
     * {@link wx.xml.xalan.xpath.patterns.NodeTest#SCORE_NSWILD},
     * {@link wx.xml.xalan.xpath.patterns.NodeTest#SCORE_QNAME}, or
     * {@link wx.xml.xalan.xpath.patterns.NodeTest#SCORE_OTHER}.
     * @throws javax.xml.transform.TransformerException
     */
    public XObject execute(XPathContext xctxt, int context)
        throws javax.xml.transform.TransformerException {

        DTMIterator nl    = m_functionExpr.asIterator(xctxt, context);
        XNumber     score = SCORE_NONE;

        if (null != nl) {
            int n;

            while (DTM.NULL != (n = nl.nextNode())) {
                score = (n == context) ? SCORE_OTHER : SCORE_NONE;

                if (score == SCORE_OTHER) {
                    context = n;

                    break;
                }
            }

            // nl.detach();
        }
        nl.detach();

        return score;
    }

    /**
     * Test a node to see if it matches the given node test.
     *
     * @param xctxt XPath runtime context.
     * @return {@link wx.xml.xalan.xpath.patterns.NodeTest#SCORE_NODETEST},
     * {@link wx.xml.xalan.xpath.patterns.NodeTest#SCORE_NONE},
     * {@link wx.xml.xalan.xpath.patterns.NodeTest#SCORE_NSWILD},
     * {@link wx.xml.xalan.xpath.patterns.NodeTest#SCORE_QNAME}, or
     * {@link wx.xml.xalan.xpath.patterns.NodeTest#SCORE_OTHER}.
     * @throws javax.xml.transform.TransformerException
     */
    public XObject execute(XPathContext xctxt, int context,
                           DTM dtm, int expType)
        throws javax.xml.transform.TransformerException {

        DTMIterator nl    = m_functionExpr.asIterator(xctxt, context);
        XNumber     score = SCORE_NONE;

        if (null != nl) {
            int n;

            while (DTM.NULL != (n = nl.nextNode())) {
                score = (n == context) ? SCORE_OTHER : SCORE_NONE;

                if (score == SCORE_OTHER) {
                    context = n;

                    break;
                }
            }

            nl.detach();
        }

        return score;
    }

    /**
     * Test a node to see if it matches the given node test.
     *
     * @param xctxt XPath runtime context.
     * @return {@link wx.xml.xalan.xpath.patterns.NodeTest#SCORE_NODETEST},
     * {@link wx.xml.xalan.xpath.patterns.NodeTest#SCORE_NONE},
     * {@link wx.xml.xalan.xpath.patterns.NodeTest#SCORE_NSWILD},
     * {@link wx.xml.xalan.xpath.patterns.NodeTest#SCORE_QNAME}, or
     * {@link wx.xml.xalan.xpath.patterns.NodeTest#SCORE_OTHER}.
     * @throws javax.xml.transform.TransformerException
     */
    public XObject execute(XPathContext xctxt)
        throws javax.xml.transform.TransformerException {

        int         context = xctxt.getCurrentNode();
        DTMIterator nl      = m_functionExpr.asIterator(xctxt, context);
        XNumber     score   = SCORE_NONE;

        if (null != nl) {
            int n;

            while (DTM.NULL != (n = nl.nextNode())) {
                score = (n == context) ? SCORE_OTHER : SCORE_NONE;

                if (score == SCORE_OTHER) {
                    context = n;

                    break;
                }
            }

            nl.detach();
        }

        return score;
    }

    /**
     * Call the visitor for the function.
     */
    protected void callSubtreeVisitors(XPathVisitor visitor) {
        m_functionExpr.callVisitors(new FunctionOwner(), visitor);
        super.callSubtreeVisitors(visitor);
    }

    class FunctionOwner implements ExpressionOwner {
        /**
         * @see ExpressionOwner#getExpression()
         */
        public Expression getExpression() {
            return m_functionExpr;
        }


        /**
         * @see ExpressionOwner#setExpression(Expression)
         */
        public void setExpression(Expression exp) {
            exp.exprSetParent(FunctionPattern.this);
            m_functionExpr = exp;
        }
    }

}
